How can I get the innermost template parameter type?

Question

Q

In a dummy example of a class

typedef myStruct>> mv;

int is the innermost

Answer 1

Try the following. It also returns a tuple if the template has more than one element:

#include 
#include 

template
struct innermost_impl
{
    using type = T;
};

template class E, typename T>
struct innermost_impl>
{
    using type = typename innermost_impl::type;
};

template class E, typename... Ts>
struct innermost_impl>
{
    using type = std::tuple::type...>;
};

template
using innermost = typename innermost_impl::type;

template
struct X;

static_assert(std::is_same>>>, int>::value, "");

int main()
{
}